Continuous steel strip cold-rolling mill apparatus

ABSTRACT

In a continuous steel strip cold-rolling mill apparatus wherein steel strips are welded together into a long continuous strip, stored in a looper and then cold rolled by a tandem mill, said looper is installed horizontally in a space of a factory building above overhead travelling cranes thereof.

United States Patent lnventor Yoehlnkl Kawuoko Fukuyamn-shl, Japan Appl. No. 882,824

Filed Dec. 8, 1969 Patented Nov. 9, 1971 Assignee Nippon Kohn Knbuahllti Kahlil Japan Priority Jan. 8, 1969 Japan CONTINUOUS STEEL STRIP COLD-ROLLING MILL APPARATUS ZCIIIIII, 4 Drawing l ke.

US. Cl 226/118 in. C1. B65h 17/42 [so] Fleldolsearch 72/250, 227;226/ll3,ll8,ll9

[56] References Clted UNITED STATES PATENTS 2,277,658 3/1942 Anderson 226/119 3,236,430 2/1966 Gruich..... 226/ll9 3,515,321 6/1970 Bortmas 226/ll8 Primary Examiner- Richard A. Schacher Attorney- Flynn & Frishauf ABSTRACT: In a continuous steel strip cold-rolling mill apparatus wherein steel strips are welded together into a long continuous strip, stored in a looper and then cold rolled by a tandem mill, said looper is installed horizontally in a space of a factory building above overhead travelling cranes thereof.

PATENTEUNuv 9 l9?! 3,618.8 39

SHEET 2 OF 2 FIG.4

BACKGROUND OF THE INVENTION This invention relates to a continuous cold-rolling apparatus, and more particularly to apparatus in which the looper is installed in the upper portion of a building above one or more overhead travelling cranes where restriction on space is not severe.

Steel strips or plates are generally produced by a hot-rolling step followed by a cold-rolling step. As is well known in the art, a cold-rolling operation is performed on hot-rolled steel strips after they have been pickled to remove iron oxides on their surfaces. In mass production plants the cold-rolling mill includes five tandem stands.

According to a recent engineering tendency in tandem mills, use of oil pressure mills, computer control systems and continuous mills has become the common practice. Especially oil pressure mills have already been put into commercial use in connection with tandem mills and skin pass mills. Computer control systems are also used. According to prior art cold tandem mills, as fire rolling operation '2 performed for each coil it i's necessary to stop the rolling operation each time the strip is threaded through the mill, or removed from the mill and when the coil is removed from the coiler, thus decreasing the production as well as efficiency. Further, as an inherent diffrculty of the cold rolling operation may be mentioned the problem of ofi-gauge products. More particularly, during threading and removal of the strip it is necessary to reduce the rolling speed at the leading end and the trailing end of the strip. Consequently, different from the hot-rolling operation, in the cold-rolling operation wherein'the gauge of the rolled strip is greatly'influenced by the rolling speed, due to the fact that the rolling surface of the rolls becomes flat due to elastic deformation, a decrease in the rolling speed reflects in the flatness of the rolling surface and hence in the gauge of the rolled strip thus resulting in the increase in the strip gauge even under a constant reduction rate. As a consequence, the leading end and the trailing end of a length of strip become offguage, such ends being too thick and are to be discarded as scraps, thus decreasing the yield of acceptable product.

Furthermore, during threading and removal of the strip, scratches are often formed on the surface of rolls to decrease the yield, thus requiring frequent roll change. This also decreases the production efficiency and increases the operating cost. Further, as the configuration of hot-rolled strips is different from one coil to the other, with the prior cold tandem mill automatic feeding of the strip is practically impossible.

Different from the conventional batch-type tandem mill wherein strips are rolled individually in a continuous mill, sections of strips are connected together into a long strip at the entry side just like a continuous processing line and the long strip is continuously rolled and wound into coils. Although such continuous mill can obviate various difficulties of the tandem mill, it has not yet been put into commercial use. One of the principal difficulties of the continuous mill is the necessity of using a looper to temporarily store a long strip. Thus, in order to store a length of strip it is necessary to fold it into a plurality of loops. Pit type and tower type loopers have been proposed but the former requires a deep pit, and the latter a tall tower which interferes with the operation of overhead travelling cranes. For this reason, in spite of its epoch-making progress, the continuous cold-rolling mill has not been actually used because of the limitations of loopers.

It is therefore an object of this invention to provide an improved continuous cold-rolling mill apparatus or installation with an improved looper which is inexpensive, does not occupy a large amount of floor space and does not interfere with the operation of overhead travelling cranes.

Another object of this invention is to provide an improved looper for use in a continuous steel strip cold-rolling line which is inexpensive and can store a large quantity of steel strip.

2 SUMMARY or run nvvsrmou In accordance with this invention, a cropping shear, a welder, tandem cold-rolling mill uncoilers, coilers, etc. which are normally used in a conventional continuous cold-rolling mill apparatus are installed on the factory floor adjacent a processing line according to the accepted practice. However, the looper which is installed between the welder and the rolling mill is disposed horizontally in a space of the factory building above the overhead travelling cranes thereof. Suitable guide means are provided to guide vertically the welded continuous strip to the looper from the welder and from the looper to the rolling mill.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIGS. 1, 2 and 3 diagrammatically show three types of typical prior art loopers, and

FIG. 4 shows one example of a confinuous cold-rolling apparatus utilizing a novel looper embodying this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Loopers which have been used are of the pit type or tower type, each installed on the entry side of the rolling mill.

FIG. I shows the so-called free-hanging looper which requires a pit having a depth about 18 meters. Such an arrangement requires an expensive foundation and large cost of installation since the pit occupies a large factory area. FIG. 2 shows a modified looper wherein a length of strip is passed around upper and lower rollers R and R which are arranged relatively closely spaced. Although this arrangement is more advantageous than that shown in FIG. I, the cost of the pit is expensive. FIG. 3 shows a tower-type looper. As diagrammatically shown, the height of the looper is considerably higher than the roof of an ordinary factory, often requiring a height of 25 meters. Accordingly, the stroke of overhead cranes C is limited.

As above described, the invention contemplates the present provision of an improved looper which can eliminate the disadvantages of these prior types of loopers.

With reference now to FIG. 2 diagrammatically illustrating a preferred embodiment of this invention, on the entry side of the rolling mill apparatus is shown a saddle conveyor 2 adapted to transfer coils l of hot-rolled strips. A hanger 4 operated in the vertical direction by means of an oil pressure cylinder is associated with conveyor 2 to mount coils l on a cradle 5. The coil mounted on the cradle 5 is designated by a reference character 6. In this state, a preceding coil 8 is supported by a double mandrel uncoiler 9 to be payed out toward a shear 12 through pinch rollers 11. It is to be understood that the shear is provided with suitable side guides 33 and 34 and a scrap box (not shown) to crop the ends of the strip. Cropped strips S are welded together in end-to-end relation by means of a welder 13 to form a long continuous strip which is supplied to the novel looper L.

In accordance with this invention, looper L is disposed horizontally in the space of the building above overhead travelling cranes l7 and 18 and comprises looping cars 19, 20, swing rollers 21 and guide rollers 23, 2d and 25. To guide the strip toward and away from the overhead looper there are provided guide rollers M, 15, 26 and 27 and press down rollers 16 and 29 near the floor surface. Strip 28 leaving the looper enters into a conventional five stand cold-rolling mill 30.

In operation, coils l of hot-rolled strips from a hot-rolling mill factory are mounted on the saddle conveyor 2 by means of crane l7 and are then successively mounted on cradle rollers 7 of cradle 5 by means of the hanger 4 of transfer device 3. The line is now treating a strip of coil 8 supported by the uncoiler 9, it being understood that the coil 6 on the cradle 5 is utilized as a succeeding coil to coil 8. During uncoiling of preceding coil 8 the band of the succeeding coil 6 is removed and cradle rollers 7 are driven to bring the leading end of coil 6 to align with a guide table. Then the cradle rollers 7 are further rotatw to flatten the leading end of the strip by means of a leveller d and the longitudinal axis of the strip S is aligned with the longitudinal axis oi the line by means of side guides. During this stage the strip is hung by means of an electromagnet 3i, thus preparing the succeeding coil 6 for the continuous running. After the preceding coil 8 has been completely payed out, the cradle rollers 7 are driven to feed the leading end of the strip into pinch rollers 11. Therefore, by the operation of a piston-cylinder assembly 32 the cradle is moved to the right as viewed in H6. 2 to bring the succeeding coil 6 to come into alignment with the double mandrel uncoiler 9, thus mounting succeeding coil 6 thereon.

Then the cradle 5 is restored to the original position shown in the drawing by the operation of piston-cylinder assembly 32. In this manner coils l on conveyor 2 are successively supplied to the line by the operation of cradle 5 and uncoiler 9. The strip 8 thus payed out is driven by pinch rollers ill and is centered by side guides 33. The trailing end of the preceding strip and the leading end of the succeeding strip are cropped by shear 12 to prepare for welding. immediately after passage through shear 12, the strip S is again centered by means of another side guide 34. The cropped trailing end of the preceding coil 8 and the leading end of the suc v 1 g coil 6 are butt welded by welder l3. Weld beads are removed by means of a suitable trimmer, not shown. Oxide films formed on the weld are also removed mechanically by a rotary wire brush, not shown. Alternatively, such oxide films may be removed by chemical treatment.

Thereafter the welded strip S is advanced to the abovedescribed overhead looper L via guide rollers l4 and 115. As described hereinabove the looper L is disposed horizontally in a space of the building above overhead travelling cranes l7 and 18 and the strip S is passed successively around guide roller 23, a roller of a looping car 19, guide roller 24, a roller of another looping car and guide roller and is thus folded in a plurality of parallel horizontal loops. Looping cars 19 and 20 are pulled by a winch 35 through cables W and W to move along rails R and R against the tension of the strip S. FIG. 2 shows a position of the maximum storage of the length of the strip. Movement of the looping cars 19 and 20 toward guide rollers 23, 24 and 25 decreases the length of the stored strip. In this manner, the length of the strip stored can be varied dependent upon the position oi the looping cars. The strip S is also supported by a plurality oi supporting rollers 22 and swinging rollers 21 which are swung vertically to clear looping cars 19 and 20. From the looper L the strip S is fed downwardly and then horizontally into five stand tandem cold-rolling mill via guide rollers 25, 26, 27 and 28. After cold rolling, the strip is sheared by a flying shear and wrapped around a takeup reel by a belt wrapper as is well known in the Thus, in accordance with this invention, as the looper required for welding successive strips into a long continuous strip to be subjected to a continuous cold-rolling operation is disposed horizontally in a space oi the factory building above overhead travelling cranes, the cost and space for building deep pits or towers for accommodating pit-type or tower-type loopers can be greatly reduced. Moreover, since the looper is disposed horizontally in a large space above travelling cranes, a larger quantity or length of the strip can be stored than with previous loopers. Further the novel looper occupies but little floor space and does not interfere with the running of the travelling cranes. Thus the novel looper permits maximum utilization of the continuous cold-rolling installation.

While the invention has been shown and described in terms of a preferred embodiment thereof, it will be obvious to one skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the invention as defined in the appended claims. Especially, apparatus comprising the continuous line excepting the novel looper may be of any type of conventional design.

What is claimed is:

l. A continuous steel strip cold-rolling mill comprising:

an overhead traveling crane for supplying steel stri s; conveying means receiving straps om ssld travel mg crane and conveying same;

welding means receiving said steel strips from said conveying means for welding together said supplied steel strips into a long continuous strip;

a horizontally oriented looper, providing at least two loops, located overhead of said travelling crane, said conveying means and said welding means, said looper comprising:

a plurality of vertically spaced-apart guide roller defining said at least two loops;

at least two looping cars, each cooperating with guide rollers of respective loops, and each looping car including a roller; and

means biasing said looping cars away from said respective guide rollers, said continuous strip passing around said guide rollers and said rollers of said looping cars to form said at least two loops overhead of said travelling crane, said conveying means and said welding means;

a plurality of tandem rolling stands located adjacent to said looper; and

guide means to guide said continuous strip vertically from said welding means to said looper and vertically from said looper to said rolling stands.

2. Apparatus according to claim 1, wherein each of said looping cars is mounted on horizontal rails and wherein said biasing means includes a winch coupled to said looping cars to move said looking cars horizontally away from their respective guide rollers.

l l 0 0 i 

1. A continuous steel strip cold-rolling mill comprising: an overhead traveling crane for supplying steel strips; conveying means receiving strips from said travelling crane and conveying same; welding means receiving said steel strips from said conveying means for welding together said supplied steel strips into a long continuous strip; a horizontally oriented looper, providing at least two loops, located overhead of said travelling crane, said conveying means and said welding means, said looper comprising: a plurality of vertically spaced-apart guide roller defining said at least two loops; at least two looping cars, each cooperating with guide rollers of respective loops, and each looping car including a roller; and means biasing said looping cars away from said respective guide rollers, said continuous strip passing around said guide rollers and said rollers of said looping cars to form said at least two loops overhead of said travelling crane, said conveying means and said welding means; a plurality of tandem rolling stands located adjacent to said looper; and guide means to guide said continuous strip vertically from said welding means to said looper and vertically from said looper to said rolling stands.
 2. Apparatus according to claim 1, wherein each of said looping cars is mounted on horizontal rails and wherein said biasing means includes a winch coupled to said looping cars to move said looking cars horizontally away from their respective guide rollers. 